1. Technical Field
The present invention relates to an integrated circuit device, an electronic apparatus, and a vehicle.
2. Related Art
In the related art, there are known circuit devices including time-to-digital conversion circuits. Time-to-digital conversion circuits convert times into digital values. As examples of circuit devices including such time-to-digital conversion circuits in the related art, known technologies of the related art disclosed are in, for example, JP-A-2009-246484, JP-A-2007-110370, JP-A-2010-119077, and JP-A-5-87954.
In the technologies of the related art of JP-A-2009-246484, JP-A-2007-110370, and JP-A-2010-119077, time-to-digital conversion is realized using so-called vernier delay circuits. In the vernier delay circuits, delay elements, which are semiconductor elements, are used to realize time-to-digital conversion.
JP-A-5-87954 discloses an infinitesimal time measurement device including a first quartz crystal oscillator that outputs a first clock pulse, a second quartz crystal oscillator that outputs a second clock pulse, an edge matching detection circuit, a synchronization counter, a microcomputer, and a transmission time control unit. The edge matching detection circuit detects a synchronization point of the first and second clock pulses. The synchronization counter performs a counting process in synchronization with the first and second clock pulses. The microcomputer calculates an infinitesimal time from a start pulse to a stop pulse based on a value of the synchronization counter. The transmission time control unit outputs the start pulse in accordance with an output of the edge matching detection circuit and values of the synchronization counter and the microcomputer.
In the technologies of the related art of JP-A-2009-246484, JP-A-2007-110370, and JP-A-2010-119077, the so-called vernier delay circuits are used to realize time-to-digital conversion. In the vernier delay circuits, the delay elements used to realize the time-to-digital conversion are semiconductor elements. In the time-to-digital conversion realized using the semiconductor elements, however, it is easy to improve resolution, but there is a problem that it is difficult to improve precision.
In the technology of the related art of JP-A-5-87954, two quartz crystal oscillators are used to realize time-to-digital conversion. In the technology of the related art, however, each of two oscillation circuits oscillating two quartz crystal oscillation elements is contained in each quartz crystal oscillator. Therefore, a circuit used for time measurement is realized by a different IC chip from the oscillation circuit or a circuit component. Therefore, a control process suitable for the two oscillation circuits is not realized. As a result, it is difficult to improve the high performance of the time-to-digital conversion.